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Friday, October 31, 2014

Sending entangled photons to opposite sides of the planet will require a small fleet of orbiting satellites, say physicists.

As reported by MIT Technology Review: One of the challenges that physicists face in creating a
quantum Internet is to distribute entangled photons around the planet.
The idea is that a user in Tokyo could use this entanglement to send a
perfectly secure message to somebody in Moscow or Johannesburg or New
York.

The problem is that entangled photons are
difficult to send over these distances because optical fibers absorb
then. This process of absorption limits the distance that physicists can
distribute entanglement to about 100 kilometers.

One
solution is to place quantum repeaters along a fiber that pass on the
entanglement without destroying it. Physicists are currently developing
these kinds of devices and expect to have them operating in the next few
years.

However, quantum repeaters will operate at
temperatures close to absolute zero and require their own power and
cooling infrastructure. That is all possible on land but is much harder
to make work for transoceanic cables. Which is why physicists are
looking for alternative ways to distribute entanglement over long
distances.

Today, Kristine Boone at the University of
Calgary in Canada and a few pals outline a plan to distribute
entanglement around the planet from satellites orbiting a couple of
hundred kilometers above the Earth. “Our proposed scheme relies on
realistic advances in quantum memories and quantum non-demolition
measurements and only requires a moderate number of satellites equipped
with a tangled photon pair sources,” they say.

One
feature of quantum technology is that it is rapidly changing as advances
are made in laboratories all over the planet. But any technology aboard
a satellite cannot be changed once it is launched. So a potential
danger with a satellite-based network is that it would be unable to take
advantage of important advances.

Boone and co get
around this by keeping much of the most advanced technology on the
ground. Their proposed satellites will be little more than vehicles for
producing entangled photons, a process that is relatively well
understood and straightforward to achieve.

Each
satellite will generate a constant stream of entangled pairs. Each
member of the pair will be sent to separate stations on the ground,
where it will be stored in quantum memories. In this way, the satellites
will entangle quantum memories across the globe.

The
ground stations will consist of relatively small one-meter telescopes,
aimed at the satellites as they pass overhead. These will collect
photons and direct them towards quantum memories. It is the quantum
memories that are likely to advance rapidly in the coming years.

Once
the entanglement is stored on the ground, it can then be used as needed
to send secure messages, or even sent locally across the quantum
Internet using short optical fibers.

Simon and co
perform various calculations to show that their proposal is well
founded. “We have argued that quantum repeaters based on LEO satellite
links are a viable approach to global quantum communication,” they say.

An interesting question is whether the system they propose would be better than the one we discussed last week in whichentanglement is transported around the world in quantum memories on containerships.
At first glance, that seems to have the potential to be cheaper given
that the transport infrastructure is already in place and known to be
cost-effective. By contrast, rocket launches, and the satellites they
carry, are hugely expensive.

One thing is clear.
Entanglement is set to become a valuable resource that is likely to be
bought and sold, much like oil and gas today. Just how the incipient
market for entanglement emerges will be interesting to watch.

Thursday, October 30, 2014

As reported by NASA Spaceflight: In
what is proving to be a dramatic week for space flight, United Launch
Alliance’s Atlas V rocket made its fiftieth flight on Wednesday, tasked
with orbiting the GPS IIF-8 satellite for the US Air Force. Liftoff from
SLC-41 at Cape Canaveral was on schedule at the start of an eighteen
minute window that opened at 13:21 local time (17:21 UTC).Atlas V Launch:Introduced in 2002, the Atlas V was originally developed by Lockheed
Martin for the US Air Force’s Evolved Expendable Launch Vehicle (EELV)
program, along with Boeing’s Delta IV.Based loosely on the earlier Atlas-Centaur series of rockets, the
Atlas V is a two-stage rocket with a Common Core Booster (CBC) first
stage and a Centaur upper stage.

Early
Atlas V launches were conducted by International Launch Services (ILS),
however Lockheed withdrew in 2006 ahead of the formation of United
Launch Alliance (ULA) that December.A partnership between Lockheed Martin and Boeing, ULA is responsible
for the manufacture and operation of both EELVs and the older Delta II,
as well as marketing them to US Government customers.ULA has also conducted commercial missions under contract to Lockheed
Martin for the Atlas V, and Boeing for the Delta II. The Delta IV is
not offered for commercial launches.Both the Atlas V and Delta IV were designed to be adaptable to all of
the US Air Force’s payload requirements, with multiple configurations
depending on the required capacity.For the Atlas V this meant a Light configuration with a modernised
Agena upper stage, a series of medium to intermediate configurations
with varying numbers of solid rocket boosters to increase performance,
and a Heavy configuration with two additional Common Core Boosters to
provide the maximum capacity. The Light and Heavy configurations were
cancelled and never flew.The first flight of the Atlas V took place successfully in August
2002, carrying Eutelsat’s Hot Bird 6 spacecraft (since renamed Eutelsat 8
West C).All of the rocket’s early flights carried commercial communications
satellites, with the next few launches orbiting HellasSat-2, Rainbow 1,
AMC-16 and Inmarsat-4F1. In August 2005 the sixth Atlas V embarked on
the type’s first mission for the US Government, deploying NASA’s Mars
Reconnaissance Orbiter on the first leg of its mission to the Red
Planet.The next launch in January 2006 carried the New Horizons probe, which
is currently en route to Pluto with a flyby expected next July.In April 2006 the Atlas flew its last mission for International
Launch Services, carrying SES Astra’s Astra-1KR spacecraft. Eleven
months later ULA flew its first Atlas mission, carrying six small
satellites for the Space Test Program.The only blemish on the Atlas V’s launch record to date occurred
during the rocket’s tenth flight, in June 2007. Carrying a pair of
Intruder ocean surveillance satellites, designated NROL-30 or USA-194,
for the National Reconnaissance Office, the Atlas injected its payload
into a lower than planned orbit after the upper stage ended its final
burn prematurely.The fault was later traced to a liquid hydrogen leak caused by a
faulty valve. Despite the shortfall both satellites were able to maneuver themselves into a usable orbit.The Atlas returned to flight in October 2007 with the launch of the
first Wideband Global Satcom spacecraft for the Air Force, finishing the
year with the deployment of a Quasar communications satellite for the
NRO in December.

In
2008 two Atlas V launches occurred, including the type’s first mission
from Vandenberg Air Force Base in March – using a pad which had
previously been used by the Atlas II. This launch carried a signals
intelligence satellite for the National Reconnaissance Office, while the
other launch, in April, deployed ICO Global Communications’ ICO-G1
satellite.Despite the satellite being deployed successfully, concerns regarding
the performance of the first stage on the ICO mission kept the Atlas
grounded for the rest of 2008. A year later the rocket returned to
flight, again deploying a Wideband Global Satcom communications
satellite.This was the first of five launches in 2009, including NASA’s Lunar
Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing
Satellite (LCROSS), which were deployed in June. As part of the LCROSS
mission the Atlas’ upper stage was intentionally impacted into the south
pole of the Moon.The three other launches in 2014 carried the PAN communications
satellite for an undisclosed government agency, a Defense Meteorological
Satellite Program (DMSP) weather satellite and the Intelsat 14
communications spacecraft.Four Atlas launches in 2010 carried NASA’s Solar Dynamics
Observatory, the first flight of the recoverable X-37B spacecraft, an
Advanced Extremely High Frequency military communications satellite and a
Topaz radar imaging spacecraft.Five launches in 2011 included NASA’s Juno mission to Jupiter and the
Curiosity rover bound for Mars as well as three military payloads – one
of which was a further X-37B mission.In
2012 six launches were made, including the third X-37B – which landed
earlier this month after nearly two years in orbit – three military
communications satellites, a pair of Intruder ocean surveillance
satellites and NASA’s Van Allen Probes to study Earth’s radiation belts.Last year the Atlas made eight flights; deploying NASA’s TDRS-11 data
relay satellite, Landsat 8 Earth imaging spacecraft and the MAVEN probe
to study Mars. The remaining launches carried military payloads; a
SBIRS-GEO missile defence satellite, a GPS navigation spacecraft, MUOS
and AEHF communications satellites and a Topaz radar reconnaissance bird
for the NRO.Wednesday’s launch is the eighth Atlas launch of 2014.For
Atlas, the year began with the launch of NASA’s TDRS-12 in January,
before a launch from Vandenberg carried a DMSP weather satellite into
orbit in early April.Seven days after the DMSP launch another Atlas flew from Cape
Canaveral carrying the NROL-67 payload – believed to be a successor to
the Mercury signals intelligence satellites launched in the 1990s. In
May an Atlas V carried an NRO Quasar satellite, NROL-33, into orbit.Early August saw the launch of the previous GPS satellite – GPS IIF-7
– from the Cape, followed by a commercial launch from Vandenberg with
the WorldView-3 Earth imaging satellite. The most recent Atlas launch
occurred in mid-September with the CLIO satellite. Like 2009’s PAN, CLIO
is a communications satellite launched for an undisclosed government
agency.The Atlas that launched on Wednesday had the tail number AV-050.

Wednesday’s
payload, GPS IIF-8, is the eighth Block IIF satellite in the Global
Positioning System (GPS) constellation. Used to provide navigation data
to both military and civilian users, the GPS programme began in the
1970s with the first demonstration satellite launching in February 1978.The first-generation GPS constellation consisted of ten test
satellites – an eleventh was launched by failed to achieve orbit –
operating in more highly inclined orbits than those which would later be
used for operational missions.Begun as a military programme, US President Ronald Reagan ordered
that the system be made available to civilian users once complete after
the Soviet Union shot down a Korean Air Lines Boeing 747 which strayed
into its airspace in 1983.The first operational, or Block II, GPS satellite was launched on the
maiden flight of the Delta II rocket in 1989, with all operational
spacecraft until 2009 riding to orbit atop Delta IIs. In late 1990 the
Block II spacecraft were replaced with the upgraded Block IIA, which
itself gave way to the Block IIR (Replenishment) series in 1997.The
current-generation GPS satellites, the Block IIF, are an interim series
designed to bridge the gap between the IIR and the new Block III
spacecraft which will replace them.Constructed by Boeing the new satellites are lighter than the
previous generation, achieved in part by eliminating the solid apogee
motor used to inject the satellites into their final orbit.The Atlas V and Delta IV, being far more powerful than the Delta II,
are able to place the spacecraft directly into their operational medium
Earth orbits.The first Block IIF satellite was deployed by a Delta IV in May 2010.
Of the seven launched to date, two have flown aboard Atlas Vs and the
remaining five atop Delta IVs.

Wednesday’s
launch took place from Space Launch Complex 41 at the Cape Canaveral
Air Force Station, a former Titan launch pad which was converted for the
Atlas V in the late 1990s. The complex was originally built in the
1960s for the Titan IIIC, with the Titan IIIE and Titan IV rockets later
launching from it.During the 1970s Complex 41 was the launch site for both of NASA’s
Viking missions to Mars and both Voyager missions to the Outer Planets,
which made use of the Titan IIIE with its Centaur upper stage.The final Titan IV launch from Complex 41 occurred in 1999, and was
an unsuccessful attempt to place a Defense Support Program missile
detection satellite into geostationary orbit. Demolition work on pad
structures began later the same year to set the facility up for the
Atlas V’s “clean pad” approach.Atlas rockets are assembled off-pad in the Vertical Integration
Facility, before being rolled to the launch complex atop a mobile launch
platform. By contrast the Atlas pad at Vandenberg, SLC-3E, uses a
traditional assembly-on-pad approach.

The launch on Wednesday began with ignition of the Atlas’ RD-180 main
engine 2.7 seconds before the countdown reached zero. Liftoff occurred
at the +1.1 second mark as the thrust the vehicle is producing exceeds
its weight.For
GPS launches the Atlas V flies in the 401 configuration, with a
four-meter payload fairing, a single engine Centaur upper stage and no
solid rocket motors attached to the first stage. As a result all thrust
during the early stages of flight comes from the RD-180 burning RP-1
propellant in liquid oxygen.The RD-180, which is derived from the RD-170 developed for the Soviet
Union’s Zenit and Energia rockets, is a two-chamber engine which was
first introduced on the Atlas III, a short-lived rocket which served as a
test-bed for the Atlas V development program.

Around
17.2 seconds into flight AV-050 will began a series of pitch and yaw
manoeuvres to establish the trajectory it required to reach its target
orbit.The rocket flew downrange on an azimuth of 45.8 degrees, reaching a speed of Mach 1 at around the one minute, 18.5 second mark.The vehicle passed through Max-Q, the area of maximum dynamic pressure, 90.3 seconds after liftoff.First stage flight lasted four minutes and 3.8 seconds, with
separation of the spent Common Core Booster occurring six seconds after
its engine cut off.Following
staging the second stage, the Centaur, entered its prestart phase with
ignition of its RL10A-4-2 engine taking place ten seconds later. The
payload fairing separated from the nose of the rocket eight seconds into
second stage flight.The Centaur burned for twelve minutes, 49.6 seconds, entering an
elliptical transfer orbit. Three hours, one minute and 7.3 seconds
later, after coasting to its apogee, the Centaur restarted for a brief
second burn. Lasting 89.7 seconds, this burn circularised the
spacecraft’s orbit ready for deployment.The satellite separated four minutes and 45.7 seconds after the burn
ended, or three hours, 24 minutes and 17.5 seconds after lifting off.
The target orbit for spacecraft separation is a circular
semi-synchronous orbit at an altitude of 20,448 kilometres (12,705
miles, 11,041 nautical miles) and an inclination of 55.0 degrees.Once operational GPS IIF-8 will broadcast pseudo-random noise (PRN)
code 03. The satellite will operate in slot 1 of plane E of the GPS
constellation, replacing the GPS IIR-4 satellite which was launched in
May 2000. IIR-4, which is also known as USA-150, will then be re-phased
into a reserve slot in the A plane of the constellation to replace GPS
IIA-19, the final Block IIA satellite to launch, which is being
decommissioned.The seventieth orbital launch attempt of 2014, Wednesday’s mission
comes less than twenty four hours after the failure of the United
States’ previous launch.

As reported by ScienceMag.org: Unmanned drones aren't just for warfare. In recent years, they’ve been used to map wildlife
and monitor crop growth. But current software can’t always handle the
vast volume of images they gather. Now, researchers have developed an
algorithm that will allow drones to 3D-map scores of hectares of land in
less than a day—an advance that is important for cost-effective
farming, disaster relief, and surveillance operations. “It is revolutionary for the problem of mosaicing large
volumes of imagery,” says computer scientist Dalton Rosario of the U.S.
Army Research Laboratory in Adelphi, Maryland, who was not involved
with the study.

Camera-equipped, autonomous, unmanned aerial vehicles
(UAVs) can fly low to the ground and take high-resolution images of
crops that tell farmers exactly where to plant their seeds or add
fertilizers—at a tenth the cost of flying a plane or purchasing
satellite images. To stitch the photos together into a mosaic, a
computer program needs to figure out the exact angle and position of the
camera for each picture taken in order to build a 3D model of the land.

Conventional software does that by looking at common features in
neighboring photos—for example, the same corn plant that appears in two
images—and marking them with points called tie points. The software then
tweaks its calculation of the camera positions for all the photos at
once, so that when it projects the tie points onto a 3D model, points
from different images match up to form a coherent projection of the corn
plant. This method works well for a few hundred photos, but once the
number of images exceed a thousand—typical for mapping a 40-hectare
farm—the process can take 1000 hours, an impossible load for desktop
computers.

So computer scientist Mark Pritt and colleagues at
Lockheed Martin in Gaithersburg, Maryland, took a different route. Their
computer program directly projects the points from each photo onto a 3D
space without knowing the exact shape of the land or the camera
positions. As a result, the tie points don’t necessarily match up, which
means the same corn plant can have two projections on the model. When
that happens, the algorithm automatically takes the middle point between
the two projections as the more accurate location and adjusts the
camera position accordingly, one image at a time. Because the algorithm
tweaks far fewer things at each step, the shortcut drastically speeds up
calculations. Once the software has adjusted the camera positions for
all the photos, the software repeats the entire process—starting from
projecting the points to the 3D space—to correct for any errors.

With the new algorithm, the researchers can produce a map from a thousand images in just 4 hours,
they reported this month at the annual IEEE Applied Imagery Pattern
Recognition Workshop. That means it can render a map of the land within
24 hours after the drones fly, giving farmers a head start on taking
care of their crops and enabling them to use drones routinely to monitor
crop health.

The image-mosaicing algorithm can also speed up applications of
drone imaging such as surveillance and disaster relief, says computer
scientist Kannappan Palaniappan of the University of Missouri, Columbia,
who was not involved with the study. When an earthquake strikes, for
example, rescue teams could survey the affected area with drones and
create a detailed 3D map of the damage in less than a day. The next step
for researchers, Palaniappan says, is to improve the algorithm so that
it can produce a map within minutes.

Wednesday, October 29, 2014

As reported by Fox News: The private spaceflight company SpaceX is hoping to bring a rocket
back from space and land it on a giant, floating platform in the middle
of the ocean, SpaceX founder Elon Musk said Oct. 24.

The company is expecting to try to land the booster on the platform as part of their next launch to space. Musk explained that landing a reusable rocket
on the floating platform — which measures about 300 feet long by 170
feet wide — is a big step toward bringing the company's Falcon 9 rocket
back to dry land. Musk and SpaceX hope to develop reusable rocket
systems and capsules in order to decrease the cost of access to space,
which could even make a colony on Mars a viable option at some point.

SpaceX has already successfully flown boost stages of the Falcon 9
back to Earth, landing in the ocean after delivering various payloads to
space, but the company has not attempted to land the rocket back on a
floating platform before. According to publicly released schedules,
SpaceX's next Falcon 9 launch is currently scheduled for December, when
the California-based company is expected to launch its fifth official
robotic cargo mission for NASA to the International Space Station using
the Dragon spacecraft. [SpaceX Reusable Rocket Re-entry Caught by Chase Plane (Video)]

"We're going to try to land on [the floating landing platform] on the
next flight," Musk said today during a discussion here at the
Massachusetts Institute of Technology's AeroAstro 100 conference. "If we
land on that flight, I think we'll be able to re-fly that booster."

Musk doesn't necessarily think that this first attempt will be
successful, however. The landing platform will be floating in the
Atlantic Ocean with engines that can be used to keep it in position;
however, it could still be "tricky" to land on top of it, Musk said.

Musk expects that SpaceX has about a 50 percent or less chance of
succeeding in landing on the next flyback, but future launches and
landing could have more chance of success.

Carrying almost two tons of cargo, a SpaceX Dragon capsule splashed down
west of Baja California, marking an end to the forth of 12 unmanned deliveries
by the company to the International Space Station.

"There are a lot of launches that will occur over the next year,"
Musk said. "I think it's quite likely that one of those flights, we'll
be able to land and re-fly, so I think we're quite close."

In July, SpaceX successfully brought its Falcon 9 booster in for a soft landing in the ocean
after launching to space, but they weren't able to recover the rocket
stage. After landing in the Atlantic, the Falcon 9 toppled over as
planned, but, according to a Twitter post from Musk at the time, the
boost stage broke apart shortly after the soft landing. Other than that,
the July test appeared to go as planned.

"This map displays Facebook fans of NFL teams across the United States. Each county is color-coded based on which official team page has the most 'Likes' from people who live in that county." (Facebook)

As reported by the Atlantic: Last Thursday, the Seattle Seahawks crushed the Green Bay Packers in the first regular NFL game of the season.

One way of looking at that: The 46 players wearing Seattle Seahawks
uniforms had a higher score than the 46 players in Green Bay Packers
uniforms, in a nationally televised game of American football.Another? The residents of Seahawks terrain—which stretches from the
northernmost Alaskan tundra to the potato fields of central Idaho—won
some spiritual victory against the cheeseheads of Packers territory,
which consumes all of Wisconsin and some of Michigan’s upper peninsula.We can be so precise about these geographies of fandom because the
Facebook Data Science team just released its 2014 NFL American fandom
map. The map shows every American county’s favorite professional
football team, as judged by the NFL team that Facebook users in that
county have ‘liked’ the most.The Cowboys rule a lot of land, but they’re not unambiguously “America’s Team.”The New York Times called the baseball version of the map “unprecedented,” arguing that, for questions like this, there’s no superior data set: “Fans may not list which team they favor on the census, but millions of them do make their preferences public on Facebook.”Now we can examine the football version. Here’s a larger version of the map if you want to check out your home county, but there are also some regions and phenomena that stuck out.First of all, unlike the MLB map, there’s no clear “national” team. In the baseball map,
Yankees fans functioned like cosmic background radiation. Love for the
the Bronx Bombers bubbled up in the absence of some local franchise,
appearing not only in greater New York City but also in North Carolina,
Nebraska, Nevada and New Mexico.That’s just not a feature of the NFL map. The Cowboys come closest, but they’re not “America’s team”
as unambiguously. Beyond Texas and its neighbors, the only isolated
pockets of Cowboys fandom are in southern Nevada and southeastern
Virginia. That’s it.After the Cowboys, the Broncos control a huge region. Pluralities of Broncos fans can be found all the way from three of the Four Corners to the 49th northern parallel.
Rivaling the Broncs in terms of sheer regional hegemony are the 49ers,
which rule almost all of California; and the Patriots, whose fans run
from Hartford, Connecticut to Caribou, Maine.And hopefully fans of all of those teams can work up some pity for
the New York Jets, whose supporters rule… well, nowhere. No U.S. county
has a plurality of Jets fans, at least on Facebook.Most interesting to me, though, is the Great Lakes region, where old clubs compete for dominance.Facebook Data ScienceThe
borders here become stark and stubborn. The Lions would control all of
Michigan—except for those pesky Packs in the southern Upper Peninsula.
The Colts could claim Indiana—if not for greater Gary. And Packers green
hovers at the edge of Vikings country, as if waiting to move in.Though none of these borders are quite as patchwork as the Jaguars fans tucked between Georgia’s Falcons and Panthers country:Facebook Data ScienceAnother place to check out: Los Angeles, whose residents apparently still cling to the Raiders—a franchise which abandoned the city 20 years ago.Facebook Data ScienceFacebook
is one of many tech companies that periodically releases free analyses
of data. In February, for instance, it revealed what it sees when two users fall in love.
Data like this is always fun, and helps us get at questions that are
otherwise unanswerable—but it’s also a chance to think about everything
that giant social networks like Facebook can see, things that are deeper
or more important than which team a certain county roots for.

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I have more than 25 years of experience in development, design, and mobile communications products and technology. I also enjoy skiing, hiking, scuba, tennis, reading, traveling, foreign languages, and painting. I'm an active member of the National Ski Patrol (NSP) and volunteer my time at either Loveland Ski resort, or Ski Cooper.